


12 Days Of Fic-mas 2019

by 1StarShine1



Series: Advent Calendar [1]
Category: Undertale (Video Game)
Genre: ALL THE FLUFF, Alternate Universe - Swapfell (Undertale), Alternate Universe - Underfell (Undertale), Alternate Universe - Underswap (Undertale), It's Christmas Time!!!, Other, Three Chapters For Each Of The Four AUs
Language: English
Status: Completed
Published: 2019-12-14
Updated: 2019-12-25
Packaged: 2021-02-25 06:15:00
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 12
Words: 3,740
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21791425
Author URL: https://archiveofourown.org/users/1StarShine1/pseuds/1StarShine1
Summary: Bunch of Christmas-y writing prompts because 'tis the season.
Relationships: Sans (Undertale)/Reader
Series: Advent Calendar [1]
Series URL: https://archiveofourown.org/series/1893979
Comments: 18
Kudos: 35





	1. (UT)Oh Ho The Mistletoe

**Author's Note:**

> I searched up either 'winter fluff writing prompts' or 'Christmas writing prompts' and let the lists inspire me.

❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎

It's the most wonderful time of the year.

“There'll be parties for hosting, marshmallows for toasting, and caroling out in the snow.” You sang along.

Speaking of parties you should probably be getting ready to go. Alphys and Undyne decided to throw a huge gyftmas bash and invited everyone they knew. So you donned your ugly Christmas sweater, grabbed your big tray of eggnog cupcakes with eggnog buttercream icing, and was out the door.

Thankfully even though there's the December chill there is no snow anywhere. There will still be a white Christmas, so there's no worry there. You were the third to arrive, just after the skeleton brothers. It was adorable seeing Papyrus with antlers taped to his skull and a blinking red nose strapped to his nasal aperture. The party really popped when the Dreemurr family arrived. Asgore, being such a dad, had one of those light up sweaters and garland around his horns.

This was a great day. Great friends, lots of Christmas karaoke, and delicious food. You were coming out of the kitchen from getting a refill on eggnog and you almost ran into Sans. You ended up in the side step shuffle, he would step the same time you would. You'd giggle every time, and then a raunchy whistle came from Undyne.

She's looking at the ceiling above you and Sans. You follow her line of sight and find a mistletoe hanging right above you. You cheeks start to go red. Those weebs set this up. That wasn't there when you went in the kitchen! Without second thinking you grabbed Sans by his snow scene sweater and kissed him on the cheek.

You'll get back at them for this...eventually. Let's not ruin the party now.

❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎


	2. (US)Grandma Loves Everyone

☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃

You flop down on your sofa with a sigh. You'd just gotten home from work. You'd been let go a little early because there was a threat of a big snow storm this evening and your boss thought it'd be too risky making you drive home in your little VW Bug. That worry was definitely well put, so here you are after you prepared your little apartment.

You were looking through the different Christmas movies and specials you could watch when you heard a knock at the door. At first you were confused, you weren't expecting anyone. It could have been you neighbor, Sans. You invited that little ball of sunshine of a skeleton and his brother over to bake some Christmas cookies and have a Christmas movie night. There in the doorway, with her normal travel bag, a big suitcase, and a rectangular box nearly as tall as her, was your grandmother.

“Surprise!”

“Grandma what are you doing here? What's all this?” You step aside to let her in.

“I'm making my rounds and visiting everyone for Christmas, and just as I suspected there's not much cheer in here.”

“That's! ...true.” All you had was a wreath hanging outside your front door. You never really bothered decorating indoors because for the longest time you were the only one there enjoying it.

She pulled out one of those fiber optic trees from the box and set it up in the corner. Then she proceeds to pull out all things Christmas from her suitcase while there's another knock at the door. _That_ had to be the skeleton brothers.

Sans ran in the moment you opened the door, and for a second you were worried about how your grandmother would react to a monster coming into your house. There was no need to worry because she essentially unofficially adopted them both being the sweet old lady she is. You and Sans help decorate the place while Papyrus just lazed about on the couch. When you finished, and with the blizzard raging outside you went to bake those cookies. Your grandmother was leading the group which brought back so much nostalgia. It's a happy holiday this year for sure.

☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃


	3. (UF)Decor War

❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎

There he is, that tall, scrawny Hot Topic reject. He thinks he's so cool. He may call himself 'The Great And Terrible Papyrus', but he's got nothing on you. He's as bright as a blown Christmas lights if he thinks he can decorate better than you. It seems to happen every year; you and that skeleton monster always ends up in some kind of competition. You're always trying to one up each other with outdoor Christmas decorating.

“Why don't you two just fuck already.” You weren't surprised at the sudden appearance of Sans, but you did embarrassingly sputter at his comment.

“What are you even doing here?” You finally say.

“You asked for my help with something so here I am.”

Right you did need him. This year you went all out and you needed his help to get a few things on the roof and then make sure you don't fall from there. You pulled the things and ladder from the garage and got to it. Getting the props up there was easy, getting the lights set up the way you wanted was the tedious part. Your whole house is set to light up to the beat of a Christmas song. It was a pain to rig up, but they're always so cool to watch.

“So when's the light show?” Sans gruffed as he lowered you down with his gravity magic.

“I can do it tonight.” And prove that you are the superior decorator.

❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎


	4. (SF)This Is Christmas?

☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃

“What in stars' name is that?” The rough demanding voice of your neighbor sounded.

You jumped and whirled around to acknowledge Sans. You'd like to think of your skeletal neighbor as a marshmallow with a razor blade in the middle. You were a little surprised that he was asking about the wreath you were hanging on the door. Though in hindsight you shouldn't be, given the world he grew up in.

When you explained it to him he was still confused and a little frustrated. This poor lad. Time to open his eyes to the beauty of Christmas. Though he seemed to want to keep those eyes closed. You roped both brothers into listening to a few classic carols. While Papyrus was discreetly bobbing along with the tune Sans was criticizing them for being frilly and weak.

You got their help (well more Sans's help since the other lazy bones sank into your couch) hanging your tree decorations. All the while Sans was questioning the point in what you were doing.

You had them try some of your homemade eggnog and pumpkin bread. That silenced Sans. He sat there with a puzzled look. He looked at you, eye-lights bright, that's where his interest was piqued. You offered an invitation to your traditional Christmas dinner of which you were going to pick up the fixings for after you hung that wreath. He seemed exited to join you. Anyone can celebrate given the chance.

☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃


	5. (UT)Ornamental

**Notes for the Chapter:**

> That was suppose to be a pun of sentimental but I don't know if it works. Also you can't use html in chapter titles so it's a little more confusing.

❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎

It's the first flurry of the season, and you know what that means? It's a family tradition that you'd make a homemade Christmas ornament. Now in recent years, since you've moved about five states away, you can't really have that family moment. You've always kept the tradition up though, and this year you got all your monster friends in on it.

You had all kinds of crafts, paints and glitter strewn on the card table. There was you, Papyrus, Sans, Frisk, Undyne, Alphys, and Mettaton ready to craft. You picked up a clear ornament bulb and a fine point paint brush. First you painted black diamonds in vertical lines, three each line, and as evenly spaced as you could. Then you painted lines bisecting the diamonds vertically. After that was dry, in every open space you put vibrant red circles. Finally you put silver and gold glitter over the black and red paint respectively.

This was a really fun day with your festive friends, and the cool part was all the decorations will have a place on the central Christmas tree in the monster's embassy. Your bulb, Frisk and Papyrus's 'gingerbread' people shaped from popsicles, all of them. A memory for the ages.

❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎


	6. (US)Ice Times

☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃

“HUMAN! ARE YOU READY TO GO?” That plus an accompanying knock came from your door. Today you and some of you friends were going out ice skating. There was a lake in the middle of the city park and every winter monsters that use ice magic freeze it, creating the _perfect_ skating rink. You and the skeleton brothers were going to go and be some of the first few to skate. That was Sans at the door, the little blueberry bomb excited for the day.

OK, so there were more than a few people present, but the soon-to-be icescape will be plenty big so that's a nonissue. It was so cool watching the magic race across the water making it solid. Papyrus, that show-off, was laying it on as thick as the honey he drinks like any normal drink with his skating skill. He lazily weaved through the crowd while you and Sans were still getting your bearings.

There were a few times Sans saved you from face-planting to which you were grateful. You were half expecting to have that tender Christmas movie moment. You were sort of OK with that happening, you blush thinking that.

☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃


	7. (UF)Bah Humbug

❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎

You take a deep breath taking in the cinnamon, ginger, and sugar scent in the air as you pull another tray from the oven. One of the best times of the year, the time where you make _all_ the Christmas cookies. Happy times.

“What is that smell?” Came the gruff voice of your friend. He had the habit of popping in whenever he wanted.

You whirl around with a big smile showing off your latest batch of Christmas tree sugar cookies. Sans looked on horrified at the state of your kitchen. Then he turns and walks out trying to move as fast as possible.

“Nope.” Was all he said.

You grabbed a cookie and went after him. He sat himself at the end of the couch furthest away from the kitchen. He's trying to act chill flipping through the TV channels but you can see right through him. And it has nothing to do with him being a skeleton.

“Oh, come on I'm just baking cookies. What's so bad about that?” You say hugging him from behind.

“Those ain't no regular cookies they're...” He has a haunted look as he says, “Christmas cookies.”

“Christmas isn't that bad.” You only get a grunt in response as he continues flipping channels. You sigh and start singing. “I'm dreaming of a white Christmas. Just like the ones I use to know.”

After a moment of silence he actually sang the next line. Oh if only he'd sing more often. He had a beautifully deep voice when he sang. He then snatched the cookie you were holding in front of him.

“Still hate this holiday.” He mumbled which made you giggle as you joined him.

❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎


	8. (SF)The Holiday's Not Perfection

☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃

“Where is that blasted tinsel!?”

In all honesty you never thought you'd here 'The Maleficent Sans' say that. He's been running around all morning nitpicking every detail of the Christmas party he wants to throw. From precise placement of every decoration on the tree, to bringing out the measuring tape to make sure the garland is spaced and swoops perfectly on the mantel. Your three stockings had to be hung exactly five inches apart, and there had to be the perfect amount of Christmas cheer all around.

You've been trying to tell him this whole time to step back and take a breath, but he kept brushing you off. Papyrus was slumped next to you like a lump on a log offering no help. Though come to think of it, it looked like he was actually moving things ever so slightly. You inwardly sigh. Dick. On one of his passes you hugged Sans around the waist and pulled him down beside you.

“That's it, your done.” You state.

“Unhand me I most certainly am not done!” He bemoaned.

You stood with a firm hand planted on his chest and a stern look. “You're. Done”

You went into the kitchen to get the group glasses of eggnog. When you returned Sans was pouting and not so subtly counting the 'imperfections' of the room. You roll your eyes and sit back in your spot. You unpaused the Christmas movie you had picked out hours ago when you tried to convince Sans the first time to sit.

You pulled him to your side after grabbing your 'nog. Of course Papyrus just had to comment, the smartass.

“Get a room.”

“Don't make it weird you weirdo.” Holding your glass between your thighs you blindly socked him with a pillow.

Your sure tomorrow Sans will be at it again, but right now it's perfectly imperfect.

☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃


	9. (UT)Have Some Christmas Cheer

❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎

The day had started out like any other. You were putting up some of your smaller Christmas decorations figuring there should at least some kind of cheer around your place. Then your neighbors stopped by; your monster neighbors. They were like your best friends. They were both skeletons; one tall, boisterous, and enthusiastic who lives to be the greatest at everything including friendships, that's Papyrus, and Sans; short, more reserved, and punny who lives to lovingly annoy his brother, Papyrus.

They noticed all the little Christmas figures you put out the moment they entered your apartment, and while they complimented how cool they were they weren't sure what they were for. When you explained a few of the traditions Papyrus insisted on helping you turn your place into Christmas central essentially. In a short amount of time, it looked like Christmas had exploded in your living room with garland, tinsel, and all kinds of decorations everywhere, a big tree overshadowing everything. It was the epitome of cheer, but you just weren't feeling it.

“HUMAN, WHY DO YOU LOOK SO SAD IN AN ATMOSPHERE LIKE THIS?!” Papyrus exclaimed as he returned from the kitchen with big glasses of eggnog.

“I wasn't really expecting to get in the Christmas spirit this year. This is going to be my first Christmas without my grandma. She passed away just a few months ago, and it's been rough. She and I would always get together and make a _huge_ batch of her sugar cookies. It was our Christmas tradition.”

“Why not continue the tradition as a way of honoring her?” Sans said from his spot beside you.

You never even thought about doing that. You decided to do it, much to the excitement of Papyrus. You made up three double batches of your grandma's recipe, and you had these big sheet pans you bought from a restaurant supply store. Now all these cookies weren't just for you three, you were going to make enough to give as Christmas gifts to other friends. Even still there was _a lot_ of cookies.

Amazingly you were able to fill every box evenly leaving one cookie left. That one cookie you put on a plate, grabbed a cup of eggnog, and set it on the little table that had a picture of you and your grandma the one summer you stayed at your grandparent's house.

_Merry Christmas grandma._

❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎

**Notes for the Chapter:**

> Wish I had a grandparent like that. The only grandparent I've had any extended time with would make a _nun_ look at her and go 'wow she's a f-ing bitch'. Yeah she's not a good person.


	10. (UF)Heavy Metal Christmas

☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃

You knocked on your neighbors' door, being mindful of their rather spiky wreath they had hung. You huddled against the wintry cold that was a little much for your single sweater with hand cross-stitched snowflakes on it.

The door was yanked open and you saw what had to be the best thing ever; The Great and Terrible Papyrus... in a Santa hat. Granted, the red was a lot darker than you'd expect, along with the other decorations too, but it was still great.

Sans, as his usual lazy lump self, was laying on the couch with his eyes closed. You plopped down next to him, after placing the few small gifts you brought under the tree, startling him.

“Frisk shall be arriving soon. They're just spending 'Christmas morning' with family.” Papyrus announced. “Why today is so special is beyond me.”

Yes, you and Frisk have been trying to open the monsters' views on things like Christmas with mixed results. Like the skeleton brothers for instance. They have some Christmas-like decorations, but one wrong move and you could poke an eye out.

That made you think of one of your favorite lines from a good Christmas movie. So you made the executive decision that you were going to watch A Christmas Story. It was perfect timing; the movie ended just as there was a knock at the door. You helped Frisk get their stack of presents to the tree before they pounced on Sans. You see Papyrus with a soft look very seldom seen. It's one big wholesome fluffy family scene, which is what it should be.

☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃


	11. Cratchit Christmas

❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎

It was time to break out the winter wreath. You had a small seasonal wreath you'd hang on your front door and that's about as festive as you get for whatever holiday. You happen to glance over at your neighbors' door after affixing your wreath. It looked like Christmas threw up on their door.

There was shiny red and green garland around the trim snowflake decals all around, and a vibrant forest green with gold and silver baubles on it. While you were admiring the decorations one of your neighbors stepped out. It's Sans, he must be going out for a jog. He asked you once if you wanted to join him, but you were _not_ a fan of running.

“Ready for Christmas are we?” You ask.

His eye-lights are stars as he greets you. “INDEED WE ARE. I CANT WAIT TO SEE YOUR HOLIDAY DOOR DISPLAY.”

“This is it.” You say. “Christmas was never all that big in my family.”

That wasn't by choice though. Money in your family was always pretty tight. You had nothing more than the basics even at Christmas. So yours consisted of maybe using the bonus one of your parents got to get a slue of Christmas movies from a Red Box. You marathon them while enjoying a Christmas casserole of Spam, Mac & Cheese, and green beans. A real Cratchit Christmas.

He deflated for a moment when you finished your story before perking back up. He bade you farewell to get a start on the day. Bless that little ball of energy and his charisma.

Later that night you were enjoying some eggnog when your door bursts open. There's something funny about a fuming dinosaur monster in an ugly sweater. Sans had decided to invite all your mutual friends over for a big Christmas bash.

“Let's get this party started already!” Alphys exclaimed.

❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎❄︎


	12. (SF)A Snow Day's Not Just For Kids

☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃

There was a heavy snow over the weekend bringing with it a myriad of closings, including your office. First things first, though, being a responsible adult. After a morning coffee you had to shovel out all your pathways. It's tedious, back breaking, and not fun in the slightest. But what can happen after is so worth it.

After you finished that, had a warming bowl of chicken noodle soup for lunch, and some time to relax it was time for the fun. Igloos, sculptures, snowmen you're going to build it all. The first thing you make is a chair right near your front door so you can have a place to look over your snowy creations when you're done.

On one of your passes of rolling the base of a snowman you notice your neighbor Papyrus kicking it on your snow throne. That cant be comfortable, even with his oversized coat. You just let him do whatever so long as he doesn't ruin anything you're doing. You were starting on the midsection when Papyrus's brother stomps across the yards.

“WHAT ARE YOU DOING YOU WORTHLESS MUTT?”

“Chillin'” You almost snort at his response.

“AND WHAT ARE YOU DOING HUMAN, OTHER THAN BEING A HORRIBLE INFLUENCE TO THIS LAZY LUMP.”

“Building a snowman.” You answer simply.

“YOU CALL THAT A SNOWMAN?”

“Pft I just started.”

“I'LL SHOW YOU WHAT TRUE SNOWMAN CRAFTMANSHIP IS!” He proclaims.

“Whatever dude.”

You've come to learn to just let him do him. You only focus on what you're doing, and the hot chocolate waiting to be made after this. It was also nice to hang out with them.

☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃

**Notes for the Chapter:**

> Hope y'all have a Merry Christmas <3


End file.
